Flow cell for fiber optic spectrometers and photometers

Abstract

A flow cell and flow cell system which allows for calibration of an attached sensor to be performed in place. Specifically, the ability to utilize standard addition techniques of calibration without the need to take a test sample from the process stream or remove the sensor from operating on the flow cell.

The invention claimed is: 
     
       1. A flow cell comprising:
 a first stream coupler, said first stream coupler comprising a first main body having a first hollow internal volume therein and a first connector having a first orifice therein, wherein fluid flows from said first orifice into said first hollow internal volume and vice-versa; 
 a second stream coupler, said second stream coupler comprising a second main body having a second hollow internal volume therein and a second connector having a second orifice therein, wherein fluid flows from said second orifice into said second hollow internal volume and vice-versa; 
 a first seal positioned on an end of said first hollow internal volume and including a first light window capable of transmitting light into and out of said first hollow internal volume; 
 a second seal positioned on an end of said second hollow internal volume and including a second light window capable of transmitting light into and out of said second hollow internal volume; 
 a hollow spacer between said first hollow internal volume and said second hollow internal volume; 
 an input, for directing light into said first hollow internal volume; and a detector, for detecting light exiting from said second hollow internal volume, said input and said detector together forming a sensor; 
 wherein, said first stream coupler is arranged adjacent to said second stream coupler so such that fluid flows from said first orifice through said first hollow internal volume and through said hollow spacer, to said second hollow internal volume and to said second orifice; and 
 wherein light passes from said input, through said first light window, through said first hollow internal volume and said hollow spacer, through said second hollow internal volume, and through said second light window before being detected by said detector. 
 
     
     
       2. The flow cell of  claim 1  wherein a length of said hollow spacer is variably selected to define a desired path length of light penetration through the flow cell. 
     
     
       3. The flow cell of  claim 1  further comprising a hole in said detector into which a holder may be placed. 
     
     
       4. The flow cell of  claim 3  wherein said holder comprises a material standard. 
     
     
       5. The flow cell of  claim 4  wherein said standard is a solid material. 
     
     
       6. The flow cell of  claim 5  wherein said solid material comprises glass. 
     
     
       7. The flow cell of  claim 3  wherein said holder comprises a cuvette. 
     
     
       8. The flow cell of  claim 7  wherein said cuvette is filled with a liquid and said liquid comprises a material standard. 
     
     
       9. The flow cell of  claim 8  wherein said cuvette is sealed. 
     
     
       10. The flow cell of  claim 3  wherein said holder facilitates calibration of said sensor without removing said input or said detector from said flow cell. 
     
     
       11. The flow cell of  claim 3  wherein said holder facilitates in situ testing of said sensor. 
     
     
       12. The flow cell of  claim 3  wherein said holder positions a material standard next to a process stream flowing through said flow cell such that light may penetrate both the process stream and the material standard sequentially.